Self-locking key



Jue 28, 1938.

F. SCHAEFER SELF LOCKING KEY Filed April 9, 193'/ Fla. 1.

F1a. a.

l l 1 v WITNEJJEJ Mg'mvam.

` relative to the pin, but there are no meanstorl Patented June 28,1 1938 amants PATENT OFFICE l sauf-momo m v Y Frederic schuur, rumana, n.

Application Avril s, 1937, serial N0. 135,949v

s claim. (ci. ss-asi This invention relates to self-locking keys, andv more particularly to keys comprising a cotterpin provided with a wedge for spreading the free ends of the pin after the pin is driven into position.

This self-locking key is similar to the one shown in my allowed patent application Serial No. 22,740 for Cotter-pin. 'Ihe key there shown comprises a cotter-pin having legs connected at one end by a head provided with an' opening in line with the legs. A spreading member is slidably disposed in thisopening and between the legs and is adapted to spreadapart the free ends of the legs when it is driven inwardly of the head. 'I'he spreading-member is provided with a lateral projection that limits its outward movement positively locking the spreading member inr its legs-spreading position. A

It is among the objects of this invention to provide a self-locking .key oi' the type :lust referredto in which there are means for locking the spreading member in legs-spreading position. 'I'his object is preferably accomplished by providing the cutter-pin legs and the spreading member with. detents which are brought into inter-engaging relation when the spreading meini ber is driveninto legs-spreading position.

I'he preferred embodiment of the invention is illustrated in the 'accompanying drawing in which Fig. 1 is Aan edge view of my self-locking key partly broken away; Fig. 2 isa side view thereof; Fig. 3 is aniedge view of the key with the legs-spreading member driven part way into the cotter-pin; Fig. 4 is an edge view, partly broken away, showing the spreading member in opera.- tive position; Fig. 5 is a side view of the key locked in a supporting member; and Figs. 6, 'I and 8 are enlarged cross-sections loi the key taken on the lines VI-VL VII-VII and VIII-VIII, respectively, of Figs. 2, 3 and 5.

Referringto Figs. 1 and 2 of the drawing, there is shown a Cotter-pin having resilient legs I integrally connected at one end by a head 2 in' the form of a loop provided with an opening l vin line with the` legs.y The legs are of general channel shape with their side ilanges 4 extending toward each other and with their free ends tapering toward'each. other to form end walls 6 (Fig. 2).

, Preferably, the outer portions of the legs normalmember in which it is inserted, a nail-like spreading memberor wedge 'I is slidably disposed in opening in the head and in thegrooves formed by the channel-like pin legs. When the wedge is in its inoperative position its head 8 is spaced 5 .from the Cotter-pin head and its tapered end is disposed behind end walls 6 of legs I. 'I'he diverging pin legs can thus be pinched together wlthoutinterference from the wedge suillciently to permit the key to be inserted in the desired l0 opening. To retain the wedge in the pin at all ltimes the portion of it within the pin is provided with detents 9 adapted to engage the -inner surface ot the head at the sides of opening 3 to limit outward movement of the wedge relative l5 thereto.

lIt is a feature of this invention that the cotterpin and wedge are so formed that the wedge is positively locked in its legs-spreading position so that it can not accidentallywork backwardly 20 and allowthe legs todraw together whereby the key might fall or work out of the opening in which it is disposed. Accordingly, the wedge and pin are provided `with detents which inter-engage when the wedge is driven into operative 25 position, and which can be disengaged only by pounding on the tapered end of the wedge to drive it backwardly in thecotter-pin. Preferably, a detent II is formed on the inner surface of one ilange 4 o! each leg I, the two detents 30 being on opposite sides of the wedge whereby they are diagonally oppositeeach other as shown in Figs. l and 6. The wedge is likewise provided with a pair oi' detents I2 formed on opposite sides of the wedge diagonally opposite to each other 85 the wedge and pin are assembled by upsetting the desired areas of the wedge with a tool operating on the wedge through the space formed 40 by looped head 2. y

As shown in Figs. 6 and 7, the distance between each leg detent II and opposite ilange 4, is great enough to permit the adjacent wedge detent I2 to pass the leg detent. However, as the leg de- 45 tents are disposed onopposite sides of the wedge they normally engage the opposite sides of the wedge and maintain it centered in the channellike legs, as shown in Fig. 6, so that the wedge detents can not pass the leg detents unless the latter and the adjoining faces of the wedge are separated. It is possible to eilect this separation because the leg detents are formed on diagonally opposite flanges of the legs. Accordingly, as the wedge is driven inwardly to spread the pin legs the wedge detents engage the leg detents and move or'cant them, together with the legs, laterally in opposite directions as shown in Figs. 3 and '7. Ihe canting which is thus permitted by the lloose t of the wedge in the legs separates the opposite faces of the wedge from detents Il vand permits the wedge detents to pass the feg detents.

As soon as these detents pass each other the legs spring back to their original positions as shown in Figs. 4 and 8. The wedgeis then in its operative position in which the free ends of the legs are 'spread apart far enough to prevent the key from being withdrawn from opening i3 (Fig. 5) in which lit is disposed. The only way that thewedge can be withdrawn from its legs-spreading position is by canting legs i in opposite directions, as previously explained, to permit the wedge detents vto slide back across the leg detents. As it is necessary to apply considerable force to the wedge to cause it to thus cant the pin legs, it will be understood that the likelihood of the wedge accidentally working out oi: legsspreading position is avoided.

It will be noted in Figs. 6, 7 and 8 that there must be suiiicient clearancebetween the key and the wall of opening i3 to permit the pin legs to cant as shown in Fig. 7. i

According to the provisions of the patent statutes, I have explained the principle and construction of my invention and have illustrated and described what I now consider to be its best embodiment. However, I desire to .have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

1. A self-locking key comprising a Cotter-pin having legs connected at one end by a head provided with an opening, and a spreading member slidably disposed in said opening and between said legs and provided with a detent for limiting withdrawal of the member from the pin, said member being adapted to spread apart the free ends of said legs when driven inwardly of said head, and said member and legs being provided with inter-engaging detents for retaining the member in its vRegs-spreading position.

2. A self-locking key comprising a Cotter-pin having resilient legs connected at one end by a headv provided with an opening, said legs being channel shape with their iianges extending toward each other, and a wedge slidably disposed in said openingand in said channel legs, said wedge being adapted ,to spread apart ,the Iree ends of said legs when driven inwardly of said head, and said. wedge and one of said flanges being provided with inter-engaging detents for re taining the wedge in its legs-spreading position. 3. A self-locking key comprising a cotter-pin having resilient legs connected at one end by a head provided with an opening, said legsbeing channel shape with their flanges'extending toward each other, anda wedge slidably disposed in said opening and in said channel legs, said wedge being adapted to spread apart the free ends of 'said legs when driven inwardly of said head, and said wedge and only two diagonally opposite flanges of said legs being provided with inter-engaging detents for retaining the wedge in its legs-spreading position;

4. A self-locking key comprising a cotter-pin having resilient legs connected-.at one end by a head provided with an opening, said legs being lchannel shape with their flanges extending lto- Ward each other. anda wedge slidably disposed in said opening and in saidchannel legs, said wedge being adapted to spread apart the free ends of said legs when driven inwardly of said head, only two diagonally opposite anges of said legs being provided with inwardly projecting detents, and said wedge being provided with diagonally vopposite detents adapted to `engage the sides of said leg detents to lock the wedge in its legsspreading position.

- 5. A self-locking key comprising a cotter-pin having resilient legs connected at one end by a head provided with an opening, said legs being channel shape with their anges extending toward each other, and said legs normally diverg- .ing away from each other in the direction oi maare s 

